The invention relates to a method for preparing methyl methacrylate from methacrolein and methanol using a heterogeneous catalyst.
Methyl methacrylate has been produced by oxidative esterification reactions in which decreases in pH of the reaction mixture are known to be detrimental. The prior art reports that addition of base to the reactor to raise pH is done to increase catalyst life. The solution to this problem has been to mix the base into a portion of the reaction mixture or reactants in a separate vessel, see, e.g., U.S. Pub. No. 2016/0251301. However, there is a need for a more efficient process which can provide improved selectivity.